1. Field of the Invention
The present invention relates to a signal line connecting structure for a keyboard of electronic apparatus, and particularly to a structure in which the signal lines of a printed circuit board located inside the keyboard are connected through connecting printed circuit boards to the signal lines of the main controller board located inside the main body of the apparatus.
2. Description of Related Art
In a conventional portable electronic apparatus, a keyboard is hinged at its rear end to the front end of the apparatus main body. This enables the keyboard to be laid down to have a virtually horizontal attitude when the apparatus is used, or to be raised upright to the front face of the apparatus main body in a folding position when the apparatus is transported.
The keyboard is provided with a number of key switches and also provided therein with a printed circuit board having a matrix of electrical contacts arranged in multiple rows and multiple columns in correspondence to the key switches. Also provided inside the keyboard is another printed circuit board, on which are mounted a plurality of electronic component parts including a decoding ROM which stores data for converting the row and column signals produced on the printed circuit board into code data and a CPU (central processing unit) which transfers, in the form of serial data, the code data to a main controller board located inside the apparatus main body. The keyboard printed circuit board and main controller board are connected by a connection cable made up of a number of signal lines.
As described above, the conventional electronic apparatus requires a keyboard printed circuit board, on which a plurality of electronic component parts such as a decoding ROM and CPU are mounted, to be located inside the keyboard, thus requiring a connection cable for connecting the keyboard printed circuit board inside the keyboard to the main controller board inside the apparatus main body. Due to the above-described structure, the conventional apparatus suffers from a high manufacturing cost and a complex keyboard structure.